The invention relates to an apparatus for emitting a jet of hot air, more especially to a hair dryer for domestic use having a cylindrical brush attached to its air outlet.
Most hair dryers for domestic use require a centrifugal blower in order to overcome the air resistance of the electric resistor in the shape of a wire coil as well as that of the brush attached to the air outlet. Since the air outlet of a centrifugal blower is at right angles to the blower axis this type of hair dryer is usually designed and built in pistol-shape:- the casing comprises a barrel which contains the electric resistor, a cylindrical blower housing to the rear of the barrel, and a grip attached to the blower housing, usually at right angles to the barrel axis. This grip also contains a switch and the electric connections and cable.
With a view to streamlining the casing and to make it lighter and handier, I have invented a hair dryer having a tubular heating element and a low-resistance brush, which is the subject of my co-pending patent application Ser. No. 662,807 filed Mar. 1, 1976 now U.S. Pat. No. 4,090,061 dated May 16, 1978. Herein the air resistance of both the heating element and the brush are low enough to permit the use of an axial fan with attached guide vanes and, accordingly, of a straight axisymmetrical casing.
It has been experienced that the tubular heating element of the said hairdryer added unnecessarily to the length of the unit, while the placement of the guide vanes necessitated an increase in the casing diameter. It is, therefore, the object of the present invention to still decrease the length and the diameter of the hair dryer by incorporating the guide vanes in the heating element proper.
In my co-pending patent application Ser. No. 662,807, filed Mar. 1, 1976, now U.S. Pat. No. 4,090,061 dated May 16, 1978. I have described and claimed an electric air heating unit comprising a centrifugal blower with its impeller peripherally enclosed by a stationary cylindrical cage of guide vanes which also serve as electric resistors for heating the passage of air through them. The heating element according to the said patent application is in the shape of a hollow cylindrical cage of longitudinal guide vanes with their leading edges in parallel, each vane forming a flat or curved, ribbon-shaped resistor; these resistor vanes are arranged to form one or several circuits adapted to be electrically energised for heating the air delivered by the impeller. In addition, they are angularly positioned to guide the air flow in a predetermined direction.